The present invention relates to a process for making a dense ternary ceramic workpiece and more particularly, to a process for making a dense Ti.sub.3 SiC.sub.2 workpiece.
A ternary titanium silicon carbide compound, having the formula Ti.sub.3 SiC.sub.2 and referred to as a 312 compound because of its 3-1-2 stoichiometry (and sometimes called titanium carbosilicide), has been the subject of recent research investigations reported in the literature. Most of these reports have been directed to Ti.sub.3 SiC.sub.2 synthesis methods and to characterization of its properties; see, e.g., Barsoum et al., J. Am. Ceram. Soc. 79: 1953-1956 (1996); Radhakrishnan et al., Scripta Materialia 34: 1809-1814 (1996); Arunajatesan et al., J. Am. Ceram. Soc. 78: 667-672 (1995); Lis et al., Materials Lett. 22: 163-168 (1995); Tong et al., J. Mater. Sci. 30: 3087-3090 (1995); Komarenko et al., Ceram. Eng. Sci. Proc. 15: 1028-1035 (1994); Okano et al., Advanced Materials '93, I, A., "Ceramics, Powders, Corrosion and Advanced Processing", Mizutani, ed., Elsevier Science B. V., Amsterdam, pp. 597-600 (1994); Racault et al., J. Mater. Sci. 29: 3384-3392 (1994); Pampuch et al., J. Mater. Syn. Proc. 1: 93-100 (1993); and Pampuch et al., J. Europ. Ceram. Soc. 5: 283-287 (1989).
Several reports describe use of or formation of Ti.sub.3 SiC.sub.2 as a bonding agent for joining silicon carbide workpieces; see, e.g., Morozumi et al., J. Mater. Sci. 20: 3976-3982 (1985) and Gottselig et al., U.S. Pat. No. 4,961,529.
The physical characteristics described for this new ceramic material suggest that Ti.sub.3 SiC.sub.2 may be a ceramic material with unusual properties superior to those of conventional brittle ceramic materials. Ti.sub.3 SiC.sub.2 is a high strength, high temperature-stable material that has been characterized as having good workability, i.e., being ductile and exhibiting plastic behavior at elevated temperatures. These workability properties are highly desirable in ceramics intended for high strength, high temperature applications.
In the fabrication of bulk workpieces using Ti.sub.3 SiC.sub.2, densification of the Ti.sub.3 SiC.sub.2 is often desirable for ensuring optimal mechanical properties in the workpiece. The present invention provides a method of producing a dense form of Ti.sub.3 SiC.sub.2 and other so-called 312 ternary compounds, in a procedure that avoids the need for high pressure densification techniques.